The list of $11$ numbers is $1$, $2$, $3$, $3$, $3$, $5$, $7$, $10$, $10$, $10$, $20$. Which of the following correctly describes the **mode** of this list?

The **mode** is the value (or values) that appear most often. Count the frequencies: $1 \to 1$, $2 \to 1$, $3 \to 3$, $5 \to 1$, $7 \to 1$, $10 \to 3$, $20 \to 1$. Both $3$ and $10$ tie at frequency $3$, and every other value has lower frequency. A list with two modes is called **bimodal**. - A and B each pick just one of the two modes — neither alone is right. - D would only be correct if no value repeated.